And alfred pfann



1 2 snees-sheet -11 G. 89 A. PANNKGHE. ELEOTB CONVERTER.

" (No Modell) 'INVENTORSi ma amm PETERS En., msnmqm` n. c.

UNITED STATES I PATENT Crrlcn.

GUSTAY PFANNKUCHE, F EXETER, NEW HAMPSHIRE, AND ALFRED PFANN- KCHE, CF CLEVELAND, OHIO, ASSIGNORS TO THE BRUSH ELECTRIC COM- PANY, or CLEVELAND, onto.

ELECTRICJCONVERTER.

l SPECIFICATION forming part of Letters Patent No. 499,852, dated .Tune 20, 1893.

Application ined May 13,1887. sei-n1 No. 239.084. (No man.)

To all whom t may concern:

' Be itknown that we, GUsTAv PFANNKUCHE, a residentot Exeter, Rockingham county, in the State of New Hampshire, and ALFRED 5 PFANNKUCHE,a resident ot Cleveland, in the State of Ohio, have invented certain new and -usetul Improvements in Electric Converters or Inductoriums, ofwhich the following is a specification.

to This invention relates to inductoriums or induction coils and especially to those inductorin ms which are employed for converting or translating .a current of one character on 'a primary circuit into a current ot another x5 character on a secondary'circuit. Inducto* rinms of this class are commonly known as electric converters or transformers or transformators, or inductive translators. They are chiefly employed in those systems zo of electric distribution wherein a current of high electro-motive Jforce is transmitted to a distance over a line circuit which is connected to the primarywire of the converter, 'and .a current of considerable density andvolume and of low electro-motive force is induced in the secondary wire of the converter, which is connected with a local or secondary circuit in which are installed incandescentl electric lamps or otherdevices for consuming electric 3o energy. Such a system admits ot the transmission of the electric energy to great distances over a small and consequently cheap conducting wire and with but little loss ot potential, and enables a unit'orm current from one central generating station to'be translated into currents of different characters at several different consu ming stations, according to the varying Wants ot different subscribers or consumers. For the operation of 4o such a system it is essential that the primary circuit be fed with a current the potential of which is subject to rapid and continual l'luc- -tuation. For this purpose alternating currents have been employed. Continuous currents have also been suggested, the requisite fluctuation to be obtained by rapidly interrupting the current after the manner ot' a y rheotome, by means of a coxnmnlator. The

' latter method is in'ipracticable on account of 5o the heavy sparking which would result. The

formern method has proved practicable but is nevertheless subject to certain disadvantages. A third method consists in the employment o t' intense pulsatory currents ot continuous direction, or currents which are subject to a rapid and continual rise and fall of potential Without being reversed or alternated. This method, which possesses all the advantages of an alternating 'currentand has a contin nous current, is fully disclosed in an application for a patent for systems and apparatus for the production vand distribu tion ot electric energy which We havel executed and are about to"`ile. For the operation of the improved converters which we are about to describe herein, We prefer to employ a pnlsatory current of the character described in ,that application.

When an electric current is passing thro ugh 7o a wire the wire-becomes surrounded by a tubular field of force, that`\is, by` magnetic lines ot force which circle round the wire in a direction depending on the direction in which the current is passing through. the wire. These lines of force are commonly called the f magnetic whirlf The density of the field Y of force is greatest close to the Wire and de creases in proportion to the square of the disbrought into close prcximitywith'the excited wire so that the lines ot force-circling round the latter shall cut the second Wire, a momentary current will be induced therein in the wire. Cr, in the case oF two parallel wires in close proximity the establishing of a current vin one wire, or a rise ot potential in a current already established therein, will induce a momentary current in the opposite direction in 9o' the other wire. Inversely, the cessation of the 'curi-ent, or a fall in the potential of the current, in the primary wire will induce in ,the secondary. wire another momentary current ofthe same direction as the primarycur- 95 rent but ot' opposite direction to the first secondary current. A reversal of the primary currentr will produce the same effect in the secondary wire. Thus, whenever the potenl tial ol. the primary current is either rising or Ico in addition the properties and capabilities ot' 6e tance from the current. It a second Wire is 8o opposite direction to the current in the first falling, either entirely on one side of what we may term the Zero linctas in a pulsatory current) or from one side to the 'other thereof (as in an alternating current), there results aiseeondary current whichv ilows in one direction during a rising` positive (or falling negative) potential, and in the opposite direction during a falling positive (or rising negative) ptential.

in order to getthe best inductive edect from the magnetic whirls around the primary wire it is necessary to bring the secondary wire into the densest portion ot the field ot force, or in other words, to bring it as close as possi` ble to the primary wire. To this end, in the construction of our improved converter We make the secondary conductor in the form of a tube and draw it closely over a well insulated primary conducting wire. Thus the conducting cross-section of the secondary con-l ductor occu ies necessarily,`- with the exception of the hickness of the insulating mate- 1ial,- the densest portion ot' the field efforce. This arrangement xnayalso be reversed-that is to say the primary conductor may be made in the form of a tube with the secondary conductor placed inside oi' it.

in order to most economically utilize the i'eld of force generated in the primary conductor," it is necessary to prevent the wasting or scattering of the lines of force, and to so concentrate them that they shall act most effectively on the secondary conductor. To this end the employment of a mass of niagnetic material, such 'as sott iron, is useful, and many methods have been proposed for accomplishing this resnlt,'such for instance as winding the primary and secondary wires on an iron core, the endsof the latter being` preferably united to form a closed magnetic circuit; and such also as winding upon a coil of the primary and secondary Wire an outer covering or envelope of sott iron wire. According to our invention we accomplish this object by inclosing the primary and secondary inductors in a magnetic field of tubular i'orm, such as a softiron tubeor pipe.

According toa further improvementintroduced by our present invention we utilize tue magnetic tubular shield as the secondary conductor. To this end we draw awell insulated copper wire or other suitable primary conductor into the bore of an iron tubei the latter being made of sufficient diameter to aifordthe requisite conductivity for the secondary current. Furthermore in order to generate in thc secondary conductor a current of sufticient density weemploy two 0r more primary conductors connected in series and pass them together through the tubular secondary conductor, whereby the density of the secondary current is as much greater than would be induced by the current through a single primary conductor as is the product ot such density multiplied bythe number of primary conductors so employed.

Our invention provides an electric con i tive view illustrating one method et a verter or inductcrium embodying the features which we have thus tar describet'twith also other' features ot construction by which it may be rendered applicable to a great variety of conditions, both electrical and me-V chanical.

Wvo will now proceed to describe'onr invention in detail with reference to the accompanying drawings, wherein Figure l includes a transverse section and a partially dissected side view ot one con struction ot inductive conductors accordingI to our invention. Figs. 2, 3, i7 5, d, 7 and S are similar sectional and side views showimi` other constructions. Fig. itis a transverse section showing a modified construction. Fig. l0 includes a section and dissected side view of another modiiied construction. Fig. ll is a' perspective view partiallydissected showing another modification. Fig. 12 is a transverse section. of a modification of the construction shown in Fig. ll.v Figs. 13', lst and l5 are transverse sections ot still other modifications. Fig. lG-is a diagrammatic view partially'in perspective illustrating a simple arrangement of circuit connection. Fig. 17 is a perspec- ,iilying our invention in connection with a iding and air line Wires. Fig. 18 is a diagram per I taining tothe construction shown in Fig. 16. Fig. 19 is a side elevation ot an inductive bat- `Fig. 2O is a plan thereof partly in hor vot the conductors are shown the primary contube Z1.

ductors are drawn in solidl black while the secondary conductors are tinted with section shading.

Fig. insulation t' around which is drawn a copper The wire a is the prinrary conductor and the Wire I) the secondary. latter are indicated some ot the lines of force of the magnetic whirl duc to-the primary current. (The iines ot force due to the secondary current are not shown.) it is obvious that with secondary conductor ot tubular forni drawn closely larou nd the primary cond uctor, the densest portion ci the held of torce that it is possible to reach is occupied by the ondaryconductor, so that the maximum inductive effect is necessarily realized. Compound condnctors ot" this construction may bc 'made by taking a well insulated copper V"#'re insulating wrapping it'desired.

With the construction just described only 'a portion of the lines ot force wouldbe utilized for inductive work.' We therefore in order to concentrate the lines otitorce and form. a magnetic closed circuit around the conduct l shows aV copper wire a incloscd in .an

Around the A YIO ors inclose the latter in a magnetic envelope or shea-th. This may be done in various ways some examples of which. we have shown.

Fig. 2 shows theV conductors constructed as in Fig. l with the addition of a tube d N soft iron within which the conductors d .tre

placed, a layer of insulating material being ff of soft iron are slipped overthe outer conothers paperorcii ductor, which has been previouslyrinsulated, and `are laid together face to face in such manner as to ferm a continuous tube d. The respective washersmay advantageously be slightly separated or insulated from one an- .ing varnished or by having tissue insnlati; material interleaved with them. Suchsepa un acts to prevent the formation of Foucault currents in the magnetic envelope, since such curren ts tend to assume a longitudinal direction, tiowing in `one direction along .the inner portion of the iron sheath and in the opposite direction along the outer portion thereof.l In the construction shown in Fig. 3 the suppression of Foucault currents may also be' readily effected vby slightly insulating the convolutions of iron -wire of whichthe magnetic envelope is formed.

Fig. 5 shows a reversal of the conductors a and l), the former now being employed as the secondary conductor and the latter as the pi'imary conductor. This arrangement however we do not consider so effective as that first described since the secondary conductor, being inclosed within the primary, is acted upon by lines of force circulating inside of the primary and consequentlyinthe opposite direction to the lines of force outside of the primary, so that to some extent the two sets 0f lines of force neutralize each other.-

VFig. 6 shows a construction wherein a cop per primary wire ct surrounded by insulation i is vinclosed within a secondary tubular conductor Z) d of soft iron' or other magnetic material, which serves not only as the secondary conductor l) but also performs the function of the magnetic envelope oi' sheath d already described. Thus the construction of the inductive conductors is considerably simplilied and cheapened without-the loss of any of the advantages inherent in the constructions pre-A violisly described. ln view fact that the electric conductivity of iron is. greatly inferior to that of copper, we construct the iron conductor b d of an area of cross-section enough greater than that which vwould be given to a copper conductor to at .secondary conductor l) d.

fthe Well knownl section.

plications, wherein such conversion of current is desired as is suitable for operating incandescent lamps in multiple are in the sec ondary circuit, the `proportion thus 'necessarily given to the iron tube b d is such as is most suitable for the magnetic envelope. ln this construction the generation of Foucault currents in the magnetic envelope is of no consequence, since the opposite ends of the magnetic envclope'are connected in the secondary circuit, so that the currentsthus in' duced are closed through the circuit and are not forced to eddy Within the iron sheath and thereby to waste energy by heating the iron, but are. utilized as the secondary currents of the inductoriuin. The iron tube Z) d may be slitted longitudinally in the same manner as is shown in Fig. 2, if desired.

The pair of single primary and secondary conductors shown in Fig. will, with a given primary current, generate a secondary current of given density. lf the density of the secondary currentis desired to be greater than that thus afforded, this may be accom; plished by inclcsing two, three or more primary wires within the one secondary con ductor. This construction is shown in Fig. 7 where seven primary wires are shown grouped together and inclosed within the one tubular The primary wires should be connected in series so that the same current will traverse one after another in succession and all in the same direction. rlhus, as it were, seven distinct induced currents are supe'rposed one upon anotherin the secondary conductor, all being of the same potential, so that the secondary current is given seven times the density or volume that would result from the employment of a single primary wire. inductive conductors of this character may be constructed in various ways. The primary wire or group 0f primary wires may be drawn into the bore of an iron pipe, their ends being left protruding at both ends of the iron pipe in order that the requisite connections may be made. Or the iron pipe maybe constructed in two parts diametricaily divided in longitudinal direction as indicated in Fig. S, in which case the two halves will be placed together with the primary wire or wires between them and will be fastened by an occasional winding or tying of wire or other material or by an exterior wrapping of insulating material, the latter method being the one shown in Fig. 8 at The two halves of the' tubular conductor t) d may be: in contact with cach other or they may be separated by a layer of insulating material, in which latter case they may be connected to the secondary circuit in series instead of in multiple arc, or one part maybe' connected in one secondary circuit and the other part in another secondary circuit. The tubular conductor ti (l may be still further sub-divided if desired, into three, four or more parts of equal or unequal area of cross- Fig. 9 sho vs a construction wherein IOO the external conductor is formed of four longitudinal sections.- These' sections may be insulated from one another' and connected together in series, or connected in different secondary circuits, er they may be insulated or uninsulated 'and all connected inmultiple are as may be preferred.

Fig. shows a sub-division of the secondary conductor t) d which here consists of a number of iron Wires arranged parallel to the primary wires and completely inclosing them, the whole being bound together by an external winding, as before described. vThese iron wires may be naked so that they shall all constitute practically one conductor, or they may be more or less insulatedl from one anmagnetic envelope by means ot" which the magnetic lines of force are given a closedV wrappings at intervals.

other and connected either in series or multiple, or according to some intermediate arlrangement.

In case the secondary conductor consists ot' an iron tube or'of a tubular arrangement of rigid sections it is preferable to make the conductors straight, as shown-in Figssl to 10; but when-iron Wires are employed for the external conductor it may be advantageous to construct the device in annular-form. Fig. 11 shows such a construction. ln this figure a single primary conductor a is wound into a coil of seven (more or less) convolutions and the inclosing secondary conductor consists of an iron wire b d suitably insulated and wound around parallel with the primary wire and 'in such manner as to inclose it on all sides, as clearly shown. Vit-h the proportions shown in .this lign re the induced secondary currents 'will beef considerable intensity, but -it' a secondary currentl of low potential and great density is required this may be'readily attained by winding a number of irn wires together and connecting their ends to the secondary circuit in multiple arc, as will be Well understood. Theentire coil is bound together at intervals by wrappings of wire';shown at h h.

l A coil thus constructed fully complies With the condition of our invention in that the sccondary conductor is substantially a tube inelosing the primary,'and in that the external short circuit of low resistance serves also as the secondary conductor.

Fig.- 12 is a cross-section ot' a coil similar to that shown in Fig. 11 but wherein the construction is inverted in that the iron secondary wires b are Wound as a central core and the primary wires a are laid against the exterior ot' this core and confined thereto by It is not essential to our invention that the primary conductor be round or of circular cross-section,` nor that the secondary conductor shall be a round tube erin fact that it shall be a complete tube at all, since various modifications of both may be readily devised which shall come within the proper scope of our invention. Fig. 13 illustrates one ei;-

aurple of such a modification. ln this ligure l the primary conductor u. etnisists of a flat copper strip or ribbon, covered with an insulating coating. z', and the secondary conductor b consists of'a strip of copper or soft iron, prettwo opposite sides of the copper strip a thereby almost entirely inclosing the latter. .The extreme edges of the conductor l; may be pressed together or not as desired. Fig. 14C showsa similar construction with the addition of a second fiat strip bent around the strip l) andhavingitsedgesbroughttogetherornearly so. ln this case the in ucr folded strip b may be the secondary conduc tor and maybe constructed of copper and the outer folded strip d may be of iron and constitute the magnetic envelope; or both may beot iron and constitute together the secondary conductor; or in the latter case they may be insulated from each 'series-or each maybe connected in a separate secondary circuit. Fig. 15 shows still another construction wherein the external conductor is not in fact a tube at all butis made of two strips of iron laid against opposite sides ot the primary' conducting strip or ribbon a and fastened together by a suitable external winding or otherwise. l -Having thus described a great variety ot constructions ot inductive conductors according to our invention we willA now proceed to describe some methods of coupling or connecting them in such manner as to render them conveniently applicable 'for practical use.

invention. A A. are the parallel conductors of the main or line circuitand B B are two construction illustratedin Fig'orFigS. The primary wire `dleads from one of the, line wires A, passes through' the iron tube b cl of one of the conductors B,'passes back through the iron tube ot the othuconductor, then 0nd and so on as'many times as may be desired, and finally joins the other conductor/X of the main line. Thus the primary wire forms a shunt or multiple -arc between the two wires ot the main circuihand the several primary Wires inclosed inl each of the iron tubes l) d are traversed by the same shunted or divided current in succession or serially,

compound conductors with their, primary wires protruding at the ends so that they may be connected together by twisting or coupling the ends of therespective wires to the passed back and forth through the two tubes as just described. The tubes l) d-'are -electrically connected together at one end, as shown at the leftliand in Fig. 16, and their opposite or right hand ends are connected to the leading-oft wires of the secondary circuit. These connections may readily be made by the same devices bywhich the tubes are faserahly the latter, which is bent around they Fig. 16 shows one method of applying our ofl our compound inductive conductors ot' the.

other and connected to the secondary ci reuitin y IOO again through the rst, again back to the sec- The connections are made by constructing' the Y I 25 same effect as though one unbroken wire were ytened in position, as shown in Fig. 1G. The connection at the left hand ends of the tube l consists of a pairof clamps c c embracing the apposite sides of the tube and drawn vtogether by a screw or bolt 7twliicli may also serve to fasten theni to the wall or other part tions and maybe mounted or arranged in various ways according-to the taste or desires oi the consumer, or the circumstances under which-theconnections have to be made. Fig. 17 shows one suitable arrangement. The inductive converter is here applied'by fastening it against the front wall of a buildinghas clearly shown. This arrangement adinitsof convenience in the connection of the primary terminals with the .wires A A lof the line circuit, when the latter are carried through the streets on poles.

' are'the wires of the secondary circuit leading into the building.

tubes will be less conspicuous than in the illus-v The converter trations, since they are there exaggerated in size in order to show them more clear-ly. They may be further concealed, it desired, by

' building them into the cornice or disposing them in any other manner that will suit the` convenience of the architect or builder.

It'may bedesirable to so connect the iron tubes b d that they shall constitute practically a closed magnetic circuit, although we do not consider this necessary. It desired it may be accomplished in the manner shown in Fig. 18 which is a diagram showing only the iron tubes and their connections. At one end the tubes are connected together by a solid piece or block of iron C, and at the'other end they are magnetically connected but electrically insulated by two iron blocks C C' which approach each other but are maintained very slightly separated by leaving a narrow air space or by placing a sheet of thin mica or other insulating material between them. Thus the magnetic circuit is scarcely interrupted whileelectric short circuiting between the tubes is prevented.

The number of compound conductors B B that are connected together may be multiplied to any desired extent and the connections of the primary and secondary conductors may be according to any desired system, either series or multiple or any intermediate arrangement.- We propose 'to combine them into what we may call inductive batteries consisting of a greater or less number of the compound conductors or inductive elements B B, according to circumstances. v

iVe prefer to construct the .compound conductors B B of standard lengths and dimen- -npon their projecting ends.

of a clamp c drawn together by sions, the proportions being such that with a given uniform electro-motive force for the primary current'with which they are to be used they will develop acertain standard electroinotive force or potential in the secondary conductor. For example, they may be made to give a ditereiice or potential at the opposite terminals of the secondary conductor of, say one volt or two volts. Compound conductors thus uniformly proportioned we will hei-einafter refer to as standard inductive elements.

In order to build kup an inductive battery we take a suitable number ot suchstandard elements, which being constructed in the form of straight. rods, we arrange side by side, leaving a little air space between them, and place them in a suitable frame or rack, made preferably of wood, and having thus secured them .in place we couple together the opposite ends of the primary andsecondary conductors accordingto any desired electrical arrangement.

Figs. 19 and 2() illustrate suoli a battery.

The battery here shown consists'of seventyfive elements B B each of vone volt potential,

with their secondaries coupled together inse-- ries in order todeliver a current to the secondary circuit having an electro-motive force of seventy-tive volts. There are tive rows of elements with fifteenl elements in each row. They are held in' place by being clamped.' at their upper and lower ends between notched bars n n wlrlch'lare drawn together by screw bolts p p passingthrough the bars at inter'- vals. The ends of the bars n n are confined in grooves'qg in; vertical end frames D D, which are drawn together by screw rods r r in order to make the whole structure rin. The end frames D D are mounted on 'abase plate E. The primary binding posts p p" are connected with the line conductors A A by wires a' a'and with the primary wires n. a in the elements-B B by means of wires a, a, and the primary wires are connected together from one element to. another by connections t if. The terminals of the secondary circuit S are connected to binding-posts s s which are joined by wires b h to the secondary conductors b b of the first and last elements B B ot the series, and the secondary conductors are connected together from'one element to another by connections c c. simplicity we have illustrated in these figures the construction of compound conductor or inductive element B shown in Fig. 6, wherein only a single primary wire is iiiclcsed in the secondary tube. Fig. 2l shows the preferred method of connecting together the terminals of the respectf ive primary and secondary' conductors of adjoining elenients. The primary wire a of each element protrudes beyond the secondary tubes b d, and a coupling or bridge t isslipped The terminals of the secondary tube are connected by means a'screw. u as shown in Figs. 2l and 22.- 1-

The inductive converters providedby our IIO For the sake of present invention possess the important advantage/s of a high inductive etiiciency, cheap- .iess and ease of manufacture, simplicity of construction,interchangeability ot' part-st and 5 great adaptability/.to different conditions by the 4facility with which -the conductors may be coupled in different arrangements, and the potential in the secondary conductor may be increased or diminished at will. 5y our conro struction of an inductive batteryit is easy to add a few elements or to take out afew, either permanently or temporarily; for the latter purpose the couplings may' be shifted by hand r the connections may be changed-by means i5 t aswitch or commutator. ln this way the battery may be adapted to any possible difference f potential that may eXist in different portions of long main circuits; or variations of potential occurring from time to time ze may be compensated for.

-What we claim as our invention, and desire to secure by Letters Patent, is, in indnctoriums or inductive converters, the following' defined novel features and combinations, snb- 257 sltagntiadiy as hereinbefore specitied, namely:

l. ln an electric converter the combination of a primary conductor with a secondary conductor of magnetic material arranged to inclose or nearly inclose the primar f, whereby 3Q it constitutes a magnetic envelope for the lines'of force. l

2. 4ln an electric converter the combination of a primary conductor with a tubular sec' ondary conductor ,of magnetic material ar- .35 ranged to in close the primary, whereby it con- -5cl Videdlongit-udinally into two or more sec:

tions, with insulating material intervening between the sections, whereby the latter may constitute distinct conductors.

5. in an. electric converter the combination of a primary conductor with asecondary conductor consisting er" an iron. tube inclosing the primary conductor.

6. in an electric converter the combination of a tubular secondary conductor of magnetic material with two or more primary conductors passing through it and insulated from one another. y

7. in an electric converter the combination of two or more tubular secondary conductors ot magnetic material with two or more primary conductors passing through them and connected in series, whereby the primary current passes Within each secondary conductor two or more times in thesame direction.

8. lin an electric converter battery the combination of a number of inductive elements,

each consisting of a primary and secondary conductor laidparallel, the several elements arrangedA parallel with one another in the saine planawit-h notched bars engaging said elements lbetween themand with clamping screwsengaging said bars and adapted to draw them together to clamp the elements conductor laid parallel, the several elements l arranged parallel with one another in sets the elements of each set being disposed in the same plane and the several sets of elements being arranged in approximately parallel planes, with a clamping frame consisting of bars arranged on opposite sides of the elements of each set and between the respective sets of elements,A and clampinga screws for drawing said bars together and thereby clam ping the several elements between them.

in witness Wh erect we have hereunto signed our names each in the presence ot two subscribing witnesses.

GUSTAV PFANNKUCIIE. ALFRED PFANNKUCHE. W'itnesses to the signature of Gustav Pfannkuche:

ARTHUR C. FRASER, GEORGE H. FRASER. W'itnesses tothe signature of Alfred Pfannkuche:

' GEORGE STosKoPF,

GEORGE C. WING. 

